The present invention relates to signal switching apparatus, and more particularly to apparatus for selectively enabling reception of cable television signals at subscriber locations.
In cable television networks, subscribers are connected with the aid of signal distribution devices to a transmission line carrying television programs, radio programs, and associated data.
A disadvantage with most conventional cable television systems is that only subscribers who indicate that they want to receive cable television services are connected to the distribution system. Installation of new subscribers requires a technician to travel to the subscriber's residence to physically connect the cable. Upon a termination of service, a technician has to travel again to the residence to disconnect the subscriber from the distribution network.
Certain programs transmitted over the cable television network are premium programs that the subscriber must pay an additional fee to receive. In the past, subscribers have been authorized to receive such programs in various ways. In some systems, a technician must travel to the subscriber's residence to install or remove traps (i.e., signal filters) or descramblers in the subscriber drop. In other systems, addressable converter/descramblers are provided to the subscribers. A cable system operator then authorizes or deauthorizes the receipt of programs by transmitting control signals to each subscriber's addressable converter. Although this technique has been very successful, it is somewhat expensive due to the converter hardware requirements.
It would be advantageous to provide a relatively inexpensive signal distribution device that could be remotely controlled from a cable television headend to enable or disable the reception of particular cable television channels by individual subscribers. It would be further advantageous to provide such a distribution device that can be economically installed at each residence in a neighborhood during the original installation of a cable television network, regardless of whether or not those living at the residence intend to become cable subscribers. It would be further advantageous for such a device to enable the selective coupling and decoupling of a plurality of signal traps in series with a subscriber drop to enable and disable the reception of designated program channels. Such a device should permit the cable system operator to switch the traps in and out of the subscriber drop without allowing subscribers or others to switch the traps themselves.
It would be further advantageous to provide the distribution device with an off position wherein cable television signals carried on the transmission line are blocked from entering residences of those who are not subscribers. Such an off position would also enable the remote disconnection of terminated subscribers.
The present invention provides such a distribution device.